I have no idea. I was supposed to be connecting in Minneapolis, they said "hey, you're probably going to miss that flight so we'll put you on this one to Detroit instead, you'll be fine", and then my flight to Detroit was delayed and we sat on the tarmac at the other end for 45 minutes so I missed my connection anyway.

And apparently Detroit only does one flight to Gatwick a day. And they wouldn't let me switch to an earlier flight that connected somewhere else or went to Heathrow because they don't let you do that if you have checked bags, or something?